1.Definition: any structure that makes progress difficult

Related Noun(s):impediment, impedimenta, obstructer, obstructor

Category: Objects

2.Definition: getting in someone's way

Category: General

3.Definition: something immaterial that stands in the way and must be circumvented or surmounted

"Lack of imagination is an obstacle to one's advancement", "The poverty of a district is an obstacle to good education", "The filibuster was a major obstruction to the success of their plan"

Related Noun(s):obstacle

Category: General

4.Definition: the act of obstructing

"Obstruction of justice"

Category: General

5.Definition: the physical condition of blocking or filling a passage with an obstruction

Related Noun(s):blockage

Category: General